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1. Field of Invention
The field of art to which this invention pertains is waste water systems. More specifically, this invention relates to a waste water pumping system containing a pair of moisture sensors within said pump system with one sensor located at a lower level and one sensor located at an upper level within the pumping system.
2. Description of Related Art
Submersible pumps are often utilized in the basements of homes, commercial buildings, etc. and are designed to discharge from those buildings water or other fluids that accumulate in the sump, as happens, for example, during a storm. When fluids collect in the sump and rise to a particular level, the pump is designed to pump those liquids out of the sump. Serious monetary losses can occur if the fluids are not removed.
These pumps always operate in a wet environment and are frequently positioned within the sump where water or other fluids can accumulate. Because these pumps generally use electrical motors, it is important to the continued operation of these pumps that moisture or water does not leak into the internal workings of the pump. Such leakage into the pump could damage the operation of the pump.
One type of pump available at present includes an impeller casing having a fluid inlet and a fluid outlet with an impeller located within the casing for moving the fluid through and out the casing. The impeller is mounted on and rotated by a shaft which is driven by a motor. In modular design, this motor is located external to the impeller casing and a shaft passes from the motor through the impeller casing. The shaft and impeller are supported by bearings which are located within a housing filled with oil which also provides lubrication of the bearings and seals. Because the motor is located away from the fluid to be pumped, this type of motor is less susceptible to damage from leakage into the housing by fluids in a sump.
Another type of pump commonly used in sumps is a submersible pump. These submersible pumps are generally comprised of a pump housing which contains a motor, a shaft directed from the motor, an impeller for evacuating the fluid from within the sump, power control and sensing cords to operate the pump motor. These submersible pumps conventionally include one or more seals, particularly around the shaft. These seals are designed to prevent liquids being pumped by the submersible pump from entering the housing.
Because these submersible pumps are designed for the discharge of liquids, sewage and/or effluent, there is always the possibility that the liquids will seep around the seals and enter the inner workings of the pump. This has been a particular problem in the lower portion of the pump as it is most likely to be emersed in fluids. In addition, the lower portion of the submersible pump also contains numerous pathways in the housing that are susceptible to leaks. If the leaks become excessive, they can short out the motor, resulting not only in damage to the motor but potential damage to the building, sometimes resulting in serious monetary losses.
To the end of insuring reliable submersible pump operation, it has become conventional to include in the lower portion of these submersible pumps some form of liquid sensing probe. Many of the common submersible pump motors include such moisture sensing probes, such as motors produced by Paco(copyright), Weil, Flygt, Hydromatic(trademark), and Myers pumps. In each of these systems a liquid sensing probe extends downward into a conventional oil chamber located above the impeller near the bottom of the motor housing. This oil chamber is designed to lubricate the seals of the shaft as well as cool the shaft while it is rotating.
However, because of the tolerances that are necessary between the shaft impeller and the housing, leaks of liquids are possible around this shaft, which may result in liquids entering the oil chamber. These liquid sensing probes sense the presence of liquids and send a warning of the presence of liquids in this oil chamber. Once this warning is sent, the motor can then be removed for repair or replacement or other actions can be taken to address the potential problem of leakage.
A submersible pump including a secondary containment area with an alarm system is disclosed in U.S. Pat. No. 5,173,019. In this system, a pump assembly including an impeller mounted on a shaft includes a liquid sensor switch (70). This liquid sensor is located within a secondary containment vessel (54) to sense the presence of liquids within this section of the pump housing as shown in FIG. 4.
A pair of moisture sensing probes (52) are disclosed within a moisture barrier sump chamber (38) in U.S. Pat. No. 5,447,078. This patent discloses a submersible gear motor which includes a motor housing (24) and a gear train housing (26), which is attached to an impeller for the movement of fluids.
While the use of liquid sensing probes in conventional submersible pumps to detect the presence of water in a lower chamber of these submersible pumps has become conventional, the housing for these submersible pumps is still susceptible to leakage at other locations, particularly in the upper portion of the submersible pump, especially above the motor itself. Leakage within this section of the pump housing can also result in damage to the motor of the pump, and if left unattended, the motor can short out resulting in substantial damage to the building or home in which the pump is located. Further, such leakage may also create an electrically hazardous situation in the sump.
Accordingly, it is an object of the invention to provide a submersible pump apparatus which is easy to operate and which senses moisture which has leaked into a motor housing of the pump.
It is a further object of this invention to provide a submersible pump apparatus containing a conventional motor and impeller which contains a sensor for sensing the presence of water, both at a lower level below the motor and at an upper level with the motor.
It is a still further object of the invention to provide a submersible pump apparatus containing a pair of liquid sensing probes, one located near the bottom of the submersible pump and one located near the top of the submersible pump, which sense the presence of water before that water can damage the operation of the pump.
These and other objects and features of the present invention will be apparent to those skilled in the art from a consideration of the following detailed description, drawings and claims. The description, along with the accompanying drawings, provides a selected example of construction of the device to illustrate the invention.
In accordance with the present invention there is provided a submersible pump utilized in a sump in a commercial or residential building or in a municipal pumping station. The submersible pump includes a housing, a motor contained within the housing containing a shaft, an impeller secured to a shaft of the motor, power control and sensing cords which among other things conduct electricity to the motor to allow its operation, a lower moisture sensing probe to sense the presence of water within the housing below the motor near the bottom of the sump pump and an upper moisture sensing probe for sensing the presence of moisture within the housing at the level of the motor before the motor can be shorted out by the moisture.